Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies.

OBJECTIVE: To evaluate the extent to which circulating biomarker and supplements of vitamin D are associated with mortality from cardiovascular, cancer, or other conditions, under various circumstances. DESIGN: Systematic review and meta-analysis of observational studies and randomised controlled trials. DATA SOURCES: Medline, Embase, Cochrane Library, and reference lists of relevant studies to August 2013; correspondance with investigators. STUDY SELECTION: Observational cohort studies and randomised controlled trials in adults, which reported associations between vitamin D (measured as circulating 25-hydroxyvitamin D concentration or vitamin D supplement given singly) and cause specific mortality outcomes. DATA EXTRACTION: Data were extracted by two independent investigators, and a consensus was reached with involvement of a third. Study specific relative risks from 73 cohort studies (849,412 participants) and 22 randomised controlled trials (vitamin D given alone versus placebo or no treatment; 30,716 participants) were meta-analysed using random effects models and were grouped by study and population characteristics. RESULTS: In the primary prevention observational studies, comparing bottom versus top thirds of baseline circulating 25-hydroxyvitamin D distribution, pooled relative risks were 1.35 (95% confidence interval 1.13 to 1.61) for death from cardiovascular disease, 1.14 (1.01 to 1.29) for death from cancer, 1.30 (1.07 to 1.59) for non-vascular, non-cancer death, and 1.35 (1.22 to 1.49) for all cause mortality. Subgroup analyses in the observational studies indicated that risk of mortality was significantly higher in studies with lower baseline use of vitamin D supplements. In randomised controlled trials, relative risks for all cause mortality were 0.89 (0.80 to 0.99) for vitamin D3 supplementation and 1.04 (0.97 to 1.11) for vitamin D2 supplementation. The effects observed for vitamin D3 supplementation remained unchanged when grouped by various characteristics. However, for vitamin D2 supplementation, increased risks of mortality were observed in studies with lower intervention doses and shorter average intervention periods. CONCLUSIONS: Evidence from observational studies indicates inverse associations of circulating 25-hydroxyvitamin D with risks of death due to cardiovascular disease, cancer, and other causes. Supplementation with vitamin D3 significantly reduces overall mortality among older adults; however, before any widespread supplementation, further investigations will be required to establish the optimal dose and duration and whether vitamin D3 and D2 have different effects on mortality risk

Defining the role of medication adherence in poor glycemic control among a general adult population with diabetes.

AIMS: This study assesses the attributable impact of adherence to oral glucose medications as a risk factor for poor glycemic control in population subgroups of a large general population, using an objective medication adherence measure. METHODS: Using electronic health records data, adherence to diabetes medications over a two-year period was calculated by prescription-based Medication Possession Ratios for adults with diabetes diagnosed before January 1, 2010. Glycemic control was determined by the HbA1c test closest to the last drug prescription during 2010-2012. Poor control was defined as HbA1c>75 mmol/mol (9.0%). Medication adherence was categorized as "good" (>80%), "moderate" (50-80%), or "poor" (<50%). Logistic regression models assessed the role medication adherence plays in the association between disease duration, age, and poor glycemic control. We calculated the change in the attributable fraction of glucose control if the non-adherent diabetic medication population would become adherent by age-groups. RESULTS: Among 228,846 diabetes patients treated by oral antiglycemic medication, 46.4% had good, 28.8% had moderate, and 24.8% had poor adherence. Good adherence rates increased with increasing disease duration, while glycemic control became worse. There was a strong inverse association between adherence level and poor control (OR = 2.50; CI = 2.43-2.58), and adherence was a significant mediator between age and poor control. CONCLUSIONS: A large portion of the diabetes population is reported to have poor adherence to oral diabetes medications, which is strongly associated with poor glycemic control in all disease durations. While poor adherence does not mediate the poorer glycemic control seen in patients with longer-standing disease, it is a significant mediator of poor glycemic control among younger diabetes patients. A greater fraction of poorly controlled younger patients, compared to older patients, could be prevented if at least 80% adherence to their medications was achieved. Therefore, our results suggest that interventions to improve adherence should focus on this younger sub-group

Development of a risk score for predicting the benefit versus harm of extending dual antiplatelet therapy beyond 6 months following percutaneous coronary intervention for stable coronary artery disease.

BackgroundDecisions on dual antiplatelet therapy (DAPT) duration should balance the opposing risks of ischaemia and bleeding. Our aim was to develop a risk score to identify stable coronary artery disease (SCAD) patients undergoing PCI who would benefit or suffer from extending DAPT beyond 6 months.MethodsRetrospective analysis of a cohort of patients who completed 6 months of DAPT following PCI. Predictors of ischaemic and bleeding events for the 6-12 month period post-PCI were identified and a risk score was developed to estimate the likelihood of benefiting from extending DAPT beyond 6 months. Incidence of mortality, ischaemic and bleeding events for patients treated with DAPT for 6 vs. 6-12 months, was compared, stratified by strata of the risk score.ResultsThe study included 2,699 patients. Over 6 months' follow up, there were 78 (2.9%) ischaemic and 43 (1.6%) bleeding events. Four variables (heart failure, left ventricular ejection fraction ≤30%, left main or three vessel CAD, status post (s/p) PCI and s/p stroke) predicted ischemic events, two variables (age>75, haemoglobin ConclusionIn a population of SCAD patients who completed 6 months of DAPT, a risk score for subsequent ischaemic and bleeding events identified patients likely to benefit from continuing or stopping DAPT

Percent of study population with poor adherence and poor control by disease duration and age.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108145#pone-0108145-g002" target="_blank">Figure 2a</a> shows that there is a positive correlation between the duration of having diabetes, and the level of poor control over the disease. In other words, the longer a patient has diabetes, the poorer his control may be. Furthermore, as the duration of having diabetes increases, poor adherence to medication decreases; so medication adherence is stronger among those who have had diabetes longer. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0108145#pone-0108145-g002" target="_blank">Figure 2b</a> demonstrates that as the age group of patients with diabetes increases, both poor control of the disease and poor medication adherence decreases. In other words, control and adherence are stronger among the older age groups.</p

Patient exclusions flow chart.

<p>The figure shows the process for arriving at the final sample size. After all exclusion criteria were applied, a final study population of 228,846 patients with diabetes who had a prescription for oral anti-glycemic medications and an HbA1c test performed was yielded.</p

Multivariable Regression Analysis for Poor Glycemic Control (HbA1c>75 mmol/mol [9.0%]).

<p>*SES  =  socio-economic status.</p><p>**mo  =  months.</p><p>Multivariable Regression Analysis for Poor Glycemic Control (HbA1c>75 mmol/mol [9.0%]).</p

Demographic and clinical characteristics according to glucose control.

<p>*mo  =  months.</p><p>Demographic and clinical characteristics according to glucose control.</p